1. Field of the Invention
The present invention relates to a hearing protection earplug comprising a shell having an outer surface individually shaped according to the measured inner shape of the user's outer ear and ear canal and a functional member engaging the shell, wherein the shell is produced by an additive layer-by-layer build-up process and has an elasticity of between shore D85 and D65. The invention also relates to a corresponding manufacturing process.
2. Description of Related Art
Earplugs comprising a customized shell, i.e. a shell having an outer surface individually shaped according to the measured inner shape of the user's outer ear and ear canal, with the shell being produced by an additive layer-by-layer build-up process, are known for example from U.S. 2003/0133583 A1, according to which a shell produced by an additive layer-by-layer laser sintering of a powder material is provided with functional elements, such as component mounts and holders, cerumen-protection systems, venting channels or channel locks which keep the earplug in place in the ear canal, may be integrated directly within the customized shell. These functional elements include holders or receptacles for electronic components necessary for hearing aid devices.
Similar earplugs are described in WO 02/071794, according to which a customized shell produced by an additive layer-by-layer build-up process is adapted to receive additional components such as electronic components, battery devices, outlet to interior components, tubes, transducers and logos.
Further, it is known to provide earplugs with movable elements which are operable by the user in order to change the acoustic attenuation provided by the earplug. For example, U.S. Pat. No. 6,148,821 discloses a hearing protection earplug comprising a hollow stem, which is inserted into a mating cylindrical outer opening of the shell. The hollow stem and the cylindrical wall of the outer opening of the shell both have a radially extending aperture which may be aligned by rotating the stem relative to the shell. The distal of the hollow stem is provided with a sound attenuation filter connecting the interior of the hollow stem with a sound bore within the shell communicating with the user's ear canal. When the two apertures are aligned, sound may enter through the opening into the interior of the hollow stem, pass through the filter and reach, attenuated by the filter, the ear canal.
It is an object of the invention to provide for a hearing protection earplug which comprises a shell having an outer surface individually shaped according the measured inner shape of the user's outer ear and ear canal, wherein at least one property of the earplug can be changed by a functional member engaging the shell, and wherein the earplug should be capable of being manufactured in a particularly effective manner.
It is a further object of the invention to provide for a corresponding manufacturing process.